Hello,
I am getting NullPointerExceptions when I am trying to use the shared caching feature of cayenne.
I have 3 servers. Each server has it's own tomcat / axis webservice and I have an avarage access of about 4 - 5 connections per second. Each connection results in about 3 - 4 select queries and about 20% of the connections result in an additional 2 - 3 insert / update queries. So the servers are working at pretty heavy load.
Yesterday I implemented the usage of cayenne's (remote) shared caching feature using JavaGroups and at first everything seemed to work just fine. But after about 1 hour, one of the servers started to produce NullPointerExceptions on every connection. i found this bug ( http://issues.apache.org/cayenne/browse/CAY-565 ) which seems to address my problem but the status is resolved?!
i tried cayenne 1.2 and 1.2B1 and in both cases got this exceptions but only if shared caching is activated. When I deactivate caching everything seems to work fine again.
It seems that there is a problem with the syncronization. This error occursed when under heavy load and a lot of threads are active at the same time. But if it is really a syncronization problem the same error could occure on every system (even if much more unlikely) even if not under heavy load.
Cheers
Ayhan Kondoz
The exception when using common-collections 3.2
[11.09.06 21:30:32] (ERROR): Entry.next=null, data[removeIndex]=<ObjectId:Customer, id=534080>=org.objectstyle.cayenne.DataRo..da158[values={suspended=false, login=christian.hantke1, rec_create=Tue May 02 00:00:00 CEST 2006, rec_change=Tue May 02 20:18:34 CEST 2006, last_updated=Mon Sep 11 21:28:26 CEST 2006, cid=709779451, id=534080, mandant_id=3}, version=-9223372036854422785, replaces=-9223372036854775808] previous=<ObjectId:Customer, d=534080>=org.objectstyle.cayenne.DataRo..da158[values={suspended=false, login=christian.hantke1, rec_create=Tue May 02 00:00:00 CEST 2006, rec_change=Tue May 02 20:18:34 CEST 2006, last_updated=Mon Sep 11 21:28:26 CEST 2006, cid=709779451, id=534080, mandant_id=3}, version=-9223372036854422785, replaces=-9223372036854775808] key=<Ob
jectId:Customer, id=364956> value=org.objectstyle.cayenne.DataRo..26844[values={suspended=false, login=nadda89, rec_create=Thu Mar 30 00:00:00 CEST 2006, rec_change=Thu Mar 30 22:19:00 CEST 2006, last_updated=Fri Aug 04 16:09:35 CEST 2006, cid=705229711, id=364956, mandant_id=3}, version=-9223372036854407476, replaces=-9223372036854775808] size=10000 maxSize=10000 Please check that your keys are immutable, and that you have used synchronization properly. If so, then please report this to commons-de..akarta.apache.org as a bug.
java.lang.IllegalStateException: Entry.next=null, data[removeIndex]=<ObjectId:Customer, id=534080>=org.objectstyle.cayenne.DataRo..da158[values={suspended=false, login=christian.hantke1, rec_create=Tue May 02 00:00:00 CEST 2006, rec_change=Tue May 02 20:18:34 CEST 2006, last_updated=Mon Sep 11 21:28:26 CEST 2006, cid=709779451, id=534080, mandant_id=3}, version=-9223372036854422785, replaces=-9223372036854775808] previous=<ObjectId:Customer, id=534080>=org.objectstyle.cayenne.DataRo..da158[values={suspended=false, login=christian.hantke1, rec_create=Tue May 02 00:00:00 CEST 20 06, rec_change=Tue May 02 20:18:34 CEST 2006, last_updated=Mon Sep 11 21:28:26 CEST 2006, cid=709779451, id=534080, mandant_id=3}, version=-9223372036854422785, replaces=-9223372036854775808] key=<ObjectId:Customer, id=364956> value=org.objectstyle.cayenne.DataRo..26844[values={suspended=false, login=nadda89, rec_create=Thu Mar 30 00:00:00 CEST 2006, rec_change=Thu Mar 30 22:19:00 CEST 2006, last_updated=Fri Aug 04 16:09:35 CEST 2006, cid=705229711, id=364956, mandant_id=3}, version=-9223372036854407476, replaces=-9223372036854775808] size=10000 maxSize=10000 Please check that your keys are immutable, and that you have used synchronization properly. If so, then please report this to commons-de..akarta.apache.org as a bug.
at org.apache.commons.collections.map.LRUMap.reuseMapping(LRUMap.java:300)
at org.apache.commons.collections.map.LRUMap.addMapping(LRUMap.java:266)
at org.apache.commons.collections.map.AbstractHashedMap.put(AbstractHashedMap.java:283)
at org.objectstyle.cayenne.access.DataRowStore.processUpdatedSnapshots(DataRowStore.java:537)
at org.objectstyle.cayenne.access.DataRowStore.processSnapshotChanges(DataRowStore.java:496)
at org.objectstyle.cayenne.access.ObjectStore.snapshotsUpdatedForObjects(ObjectStore.java:559)
at org.objectstyle.cayenne.access.ObjectResolver.objectsFromDataRows(ObjectResolver.java:162)
at org.objectstyle.cayenne.access.ObjectResolver.synchronizedObjectsFromDataRows(ObjectResolver.java:137)
at org.objectstyle.cayenne.access.DataDomainQueryAction.interceptObjectConversion(DataDomainQueryAction.java:363)
at org.objectstyle.cayenne.access.DataDomainQueryAction.execute(DataDomainQueryAction.java:151)
at org.objectstyle.cayenne.access.DataDomain.onQuery(DataDomain.java:715)
at org.objectstyle.cayenne.util.ObjectContextQueryAction.runQuery(ObjectContextQueryAction.java:249)
at org.objectstyle.cayenne.access.DataContextQueryAction.execute(DataContextQueryAction.java:90)
at org.objectstyle.cayenne.access.DataContext.onQuery(DataContext.java:1320)
at org.objectstyle.cayenne.access.DataContext.performQuery(DataContext.java:1309)
The exception when using common-collections 3.1
[11.09.06 15:29:13] (ERROR):
java.lang.NullPointerException
at org.apache.commons.collections.map.LRUMap.reuseMapping(LRUMap.java:272)
at org.apache.commons.collections.map.LRUMap.addMapping(LRUMap.java:243)
at org.apache.commons.collections.map.AbstractHashedMap.put(AbstractHashedMap.java:282)
at org.objectstyle.cayenne.access.DataRowStore.processUpdatedSnapshots(DataRowStore.java:612)
at org.objectstyle.cayenne.access.DataRowStore.processSnapshotChanges(DataRowStore.java:571)
at org.objectstyle.cayenne.access.DataRowStore.snapshotsUpdatedForObjects(DataRowStore.java:313)
at org.objectstyle.cayenne.access.ObjectResolver.objectsFromDataRows(ObjectResolver.java:159)
at org.objectstyle.cayenne.access.ObjectResolver.synchronizedObjectsFromDataRows(ObjectResolver.java:134)
at org.objectstyle.cayenne.access.DataDomainQueryAction.interceptObjectConversion(DataDomainQueryAction.java:373)
at org.objectstyle.cayenne.access.DataDomainQueryAction.execute(DataDomainQueryAction.java:151)
at org.objectstyle.cayenne.access.DataDomain.onQuery(DataDomain.java:766)
at org.objectstyle.cayenne.util.ObjectContextQueryAction.runQuery(ObjectContextQueryAction.java:253)
at org.objectstyle.cayenne.access.DataContextQueryAction.execute(DataContextQueryAction.java:90)
at org.objectstyle.cayenne.access.DataContext.onQuery(DataContext.java:1422)
at org.objectstyle.cayenne.access.DataContext.performQuery(DataContext.java:1411)
Ayhan Kondoz
Software-Entwicklung
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